Hi. I am building custom device that is going to inplemented in car CANbus network.
I am still in early development but i have some dilema about programing via ICSP.
MCP2515 uses SPI comunication and those pin (MISO,MOSI,SCK) are also used for ICSP (planing to progam it with USB-Asp).
Planing to put ICSP header on board so my question is: will MCP2515 make some kind of interference while programing Atmega via ICSP?
There can be conflicts, so you have to ensure that there is ether protection for the surrounding circuits during programming or they will not source/sink current during the programming operation.
This is most critical if you use a high voltage programmer where the reset pin could reach 12V during the serial programming of the chip...
Part of the planning stage ... There are times I put a socket on the board so I can remove mpu and re-program it... It's mostly in the design...
Look at the datasheet for the mcp2515 and see the specifications about the pins you're wanting to use...
If the mcp2515 is using active outputs then it'll probably become an issue...
Good luck
Consider using an analog switch or some tristate buffers to isolate when programming.
I wasn't lazy so i made small pcb and tested, ICSP works without problem
1 Like
I have used ICSP with several SPI devices attached to the micro without issue. As long as the SPI devices' CS pin remains HIGH, the outputs should be tri-stated/floating. Pull up resistors might be necessary in some situations.
This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.